Ultrafast Lasers Improve the Efficiency of CIS Thin Film Solar Cells

CIS (Cu(In,Ga)(S,Se)2) thin film solar cells show a high potential to achieve the efficiencies of Si wafer-based solar cells. The commonly applied patterning processes for the integrated interconnects are based on nanosecond laser ablation and mechanical scribing. Both methods introduce damages on the thin films by thermal effects and mechanical forces. By picosecond laser processing we realized all three patterning steps to the monolithic thin films CIS modules, namely the separation of the molybdenum back electrode, the absorber and the ZnO font electrode (P1, P2 and P3 respectively). We achieved an efficiency of 14.7% for 300 x 300 mm2 modules.